Abstract: An automatic music playing system including a matrix circuit and manual play switches both connected to tone signal generators, each of said manual play switches consisting of a series connection of a resistor and a switch and a capacitor connected between the interconnection of said resistor and switch and the input terminal of a corresponding tone signal generator so that the output signals of said matrix circuit is absorbed in said capacitor when said switch is closed and an on-off switch operation triggers the corresponding tone signal generator, and each of said tone signal generators including two oscillating transistors connected with a feed-back loop and provided with a damping resistor.

Abstract: A zone time display clock having a zone or locality appointing and displaying means having a form of a world map and provided with touch detecting terminals disposed on the world map and with zone illuminating means for illuminating the designated zone. The clock further comprises a reference clock, a time difference generating circuit for generating the time difference signals for the designated and the "home" localities with respect to the reference locality alternately, touch switch means for memorizing a touched place in the world map and activating the zone displaying means and the time difference generating circuit, time and date difference calculating means for calculating the time and the date difference for the designated locality with respect to the "home" locality, and display driving means for displaying the time and the date difference or the date for the designated locality.